Roll-on liquid applicators for dispensing a liquid in a controlled amount may employ a spring-biased ball which is captured within an upper chamber of a housing. In this style of applicator the ball is movable between a first or closed position and a dispensing position where the ball is moved away from an edge of the housing. Applicators of this type typically rely on sealed interfaces, not only around the ball, but with other components which are received within the housing. The effectiveness and reliability of these sealed interfaces is an important design consideration. When roll-on liquid applicators are used for dispensing a low-viscosity liquid, the design considerations for effective and reliable sealing take on added importance.
When this type of roll-on liquid applicator is not in use, it is important to prevent evaporation loss of the liquid. This design consideration is applicable for the primary liquid reservoir or supply and is applicable for the staged liquid supply which may be in a chamber which is in flow communication with and/or in direct contact with the ball. As these design aspects are evaluated relative to the potential for an improved construction, the cost of the component parts, the ease of assembly of those parts and the reliability of the fits between mating parts, including sealing integrity and overall performance, take on added importance. While the focus of the present disclosure is on a roll-on “liquid” applicator the actual construction and the design of the component parts would be applicable to any flowable media, whether a low-viscosity liquid or a flowable media with a higher viscosity. In fact, even certain powder compositions could be classified as “flowable” and the only design considerations which would have to be made would be on the size of clearance spaces and/or flow openings such that the selected flowable media would be able to pass therethrough.
When a selected manner of sealing the interface between two (2) structures introduces variables which are difficult to control or when the structures are more costly to produce, a new construction offers opportunity for improvement. For example, trying to establish a sealed interface between a conical surface and an annular edge typically leaves little margin for error if the intended area of contact is a relatively narrow line. Under these conditions, if either surface is slightly out of round or warped, the abutment between these two (2) components could leave gaps or separation which could be susceptible to liquid leakage and/or evaporation of some portion of the liquid supply, depending in part on the viscosity of the liquid. Evaporation is a greater concern when a highly volatile liquid is going to be dispensed by the applicator.
Some designs introduce component part complexities which are less reliable in terms of their fit, sealing and performance and at the same time these component parts may be more expensive to produce. If these same part complexities create abutment interfaces which are difficult to seal, a new construction offers opportunities for improvement. It might be possible to improve the overall construction of these types of roll-on applicators by the use of an additional component part. Although a reduction in the number of component parts might be thought of as always being a desirable design pursuit, sometimes adding a part can contribute to the overall reliability and performance of an assembly. This is the case with the roll-on applicator of the present disclosure.